/******************************************************************************
 *  Filename:       sw_poly1305-donna.c
 ******************************************************************************/

#include "sw_poly1305-donna.h"

#include "sw_poly1305-donna-32.h"

void poly1305_update(poly1305_context *ctx, const unsigned char *m, size_t bytes)
{
    poly1305_state_internal_t *st = (poly1305_state_internal_t *)ctx;
    size_t i;

    /* handle leftover */
    if (st->leftover)
    {
        size_t want = (poly1305_block_size - st->leftover);
        if (want > bytes)
        {
            want = bytes;
        }
        for (i = 0; i < want; i++)
        {
            st->buffer[st->leftover + i] = m[i];
        }
        bytes -= want;
        m += want;
        st->leftover += want;
        if (st->leftover < poly1305_block_size)
        {
            return;
        }
        poly1305_blocks(st, st->buffer, poly1305_block_size);
        st->leftover = 0;
    }

    /* process full blocks */
    if (bytes >= poly1305_block_size)
    {
        size_t want = (bytes & ~(poly1305_block_size - 1));
        poly1305_blocks(st, m, want);
        m += want;
        bytes -= want;
    }

    /* store leftover */
    if (bytes)
    {
        for (i = 0; i < bytes; i++)
        {
            st->buffer[st->leftover + i] = m[i];
        }
        st->leftover += bytes;
    }
}

void poly1305_auth(unsigned char mac[16], const unsigned char *m, size_t bytes, const unsigned char key[32])
{
    poly1305_context ctx;
    poly1305_init(&ctx, key);
    poly1305_update(&ctx, m, bytes);
    poly1305_finish(&ctx, mac);
}

int poly1305_verify(const unsigned char mac1[16], const unsigned char mac2[16])
{
    size_t i;
    unsigned int dif = 0;
    for (i = 0; i < 16; i++)
    {
        dif |= (mac1[i] ^ mac2[i]);
    }
    dif = (dif - 1) >> ((sizeof(unsigned int) * 8) - 1);
    return (dif & 1);
}

/* test a few basic operations */
int poly1305_power_on_self_test(void)
{
    /* example from nacl */
    static const unsigned char nacl_key[32] = {0xee, 0xa6, 0xa7, 0x25, 0x1c, 0x1e, 0x72, 0x91, 0x6d, 0x11, 0xc2,
                                               0xcb, 0x21, 0x4d, 0x3c, 0x25, 0x25, 0x39, 0x12, 0x1d, 0x8e, 0x23,
                                               0x4e, 0x65, 0x2d, 0x65, 0x1f, 0xa4, 0xc8, 0xcf, 0xf8, 0x80};

    static const unsigned char nacl_msg[131] = {0x8e, 0x99, 0x3b, 0x9f, 0x48, 0x68, 0x12, 0x73, 0xc2, 0x96, 0x50, 0xba,
                                                0x32, 0xfc, 0x76, 0xce, 0x48, 0x33, 0x2e, 0xa7, 0x16, 0x4d, 0x96, 0xa4,
                                                0x47, 0x6f, 0xb8, 0xc5, 0x31, 0xa1, 0x18, 0x6a, 0xc0, 0xdf, 0xc1, 0x7c,
                                                0x98, 0xdc, 0xe8, 0x7b, 0x4d, 0xa7, 0xf0, 0x11, 0xec, 0x48, 0xc9, 0x72,
                                                0x71, 0xd2, 0xc2, 0x0f, 0x9b, 0x92, 0x8f, 0xe2, 0x27, 0x0d, 0x6f, 0xb8,
                                                0x63, 0xd5, 0x17, 0x38, 0xb4, 0x8e, 0xee, 0xe3, 0x14, 0xa7, 0xcc, 0x8a,
                                                0xb9, 0x32, 0x16, 0x45, 0x48, 0xe5, 0x26, 0xae, 0x90, 0x22, 0x43, 0x68,
                                                0x51, 0x7a, 0xcf, 0xea, 0xbd, 0x6b, 0xb3, 0x73, 0x2b, 0xc0, 0xe9, 0xda,
                                                0x99, 0x83, 0x2b, 0x61, 0xca, 0x01, 0xb6, 0xde, 0x56, 0x24, 0x4a, 0x9e,
                                                0x88, 0xd5, 0xf9, 0xb3, 0x79, 0x73, 0xf6, 0x22, 0xa4, 0x3d, 0x14, 0xa6,
                                                0x59, 0x9b, 0x1f, 0x65, 0x4c, 0xb4, 0x5a, 0x74, 0xe3, 0x55, 0xa5};

    static const unsigned char nacl_mac[16] =
        {0xf3, 0xff, 0xc7, 0x70, 0x3f, 0x94, 0x00, 0xe5, 0x2a, 0x7d, 0xfb, 0x4b, 0x3d, 0x33, 0x05, 0xd9};

    /* generates a final value of (2^130 - 2) == 3 */
    static const unsigned char wrap_key[32] = {0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                                               0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                                               0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

    static const unsigned char wrap_msg[16] =
        {0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

    static const unsigned char wrap_mac[16] =
        {0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};

    /*
       mac of the macs of messages of length 0 to 256, where the key and messages
       have all their values set to the length
    */
    static const unsigned char total_key[32] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0xff, 0xfe, 0xfd,
                                                0xfc, 0xfb, 0xfa, 0xf9, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
                                                0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

    static const unsigned char total_mac[16] =
        {0x64, 0xaf, 0xe2, 0xe8, 0xd6, 0xad, 0x7b, 0xbd, 0xd2, 0x87, 0xf9, 0x7c, 0x44, 0x62, 0x3d, 0x39};

    poly1305_context ctx;
    poly1305_context total_ctx;
    unsigned char all_key[32];
    unsigned char all_msg[256];
    unsigned char mac[16];
    size_t i, j;
    int result = 1;

    for (i = 0; i < sizeof(mac); i++)
    {
        mac[i] = 0;
    }
    poly1305_auth(mac, nacl_msg, sizeof(nacl_msg), nacl_key);
    result &= poly1305_verify(nacl_mac, mac);

    for (i = 0; i < sizeof(mac); i++)
    {
        mac[i] = 0;
    }
    poly1305_init(&ctx, nacl_key);
    poly1305_update(&ctx, nacl_msg + 0, 32);
    poly1305_update(&ctx, nacl_msg + 32, 64);
    poly1305_update(&ctx, nacl_msg + 96, 16);
    poly1305_update(&ctx, nacl_msg + 112, 8);
    poly1305_update(&ctx, nacl_msg + 120, 4);
    poly1305_update(&ctx, nacl_msg + 124, 2);
    poly1305_update(&ctx, nacl_msg + 126, 1);
    poly1305_update(&ctx, nacl_msg + 127, 1);
    poly1305_update(&ctx, nacl_msg + 128, 1);
    poly1305_update(&ctx, nacl_msg + 129, 1);
    poly1305_update(&ctx, nacl_msg + 130, 1);
    poly1305_finish(&ctx, mac);
    result &= poly1305_verify(nacl_mac, mac);

    for (i = 0; i < sizeof(mac); i++)
    {
        mac[i] = 0;
    }
    poly1305_auth(mac, wrap_msg, sizeof(wrap_msg), wrap_key);
    result &= poly1305_verify(wrap_mac, mac);

    poly1305_init(&total_ctx, total_key);
    for (i = 0; i < 256; i++)
    {
        /* set key and message to 'i,i,i..' */
        for (j = 0; j < sizeof(all_key); j++)
        {
            all_key[j] = i;
        }
        for (j = 0; j < i; j++)
        {
            all_msg[j] = i;
        }
        poly1305_auth(mac, all_msg, i, all_key);
        poly1305_update(&total_ctx, mac, 16);
    }
    poly1305_finish(&total_ctx, mac);
    result &= poly1305_verify(total_mac, mac);

    return result;
}
